Various kinds of compressors such as a scroll type or a swash plate type, are used in various fields using hydraulic pressure, for example, an air conditioning apparatus. In general, swash plate type compressors using an inclination angle of a swash plate and employing a plurality of cylinders have been widely used to more precisely perform hydraulic control.
Among them, a variable displacement swash plate type compressor capable of continuously varying an inclination angle of a swash plate depending on variation in thermal load to control strokes of pistons to thereby perform precise flow rate control and preventing abrupt variation in torque of an engine due to the compressor to improve ride comfort of a vehicle is being widely used.
In a conventional variable displacement swash plate type compressor, since a power transmission element fixed to a drive shaft and transmitting power from a rotating lug plate to a swash plate is separate from an element for slope movement of the swash plate, the lug plate may be in direct contact with the swash plate, thus rapidly wearing a compressor member and disturbing smooth slope movement of the swash plate.
Therefore, a swash plate type compressor in which a component for rotational power transmission and a component for slope movement guide are integrated as a single body has been proposed. For example, disclosed hereinafter is a variable displacement swash plate type compressor including slide blocks installed at both side ends of a pin passing through a projection projecting from a center part of a front surface of a swash plate such that the slide blocks perform the power transmission and the slope movement guide.
FIGS. 1 to 4 show an example of a conventional variable displacement swash plate type compressor disclosed in Korean Patent Application 10-2006-0120155, which will be briefly described with reference to the drawings.
FIG. 1 is a perspective view of a conventional variable displacement swash plate type compressor 10. A pin 41 is inserted into a projection 41 formed at a front center part of a swash plate 40 and slide blocks 43 are disposed on both sides of the pin. Peripheral surfaces of the slide blocks 43 roll along slopes 34 formed in a power transmission groove 31 of a lug plate 30 to enable slope movement of the swash plate 40. In addition, the both surfaces of the slide blocks 43 transmit rotational movement of the lug plate 30 by contacting with side surfaces 35 of the power transmission groove 31. That is, direct contact between the lug plate 30 and the swash plate 40 can be prevented by a rear groove 33 in a direction of a drive shaft 20 and the slide blocks 43 in a direction of the sidewalls 35 of the lug plate 30.
FIG. 2 is an exploded perspective view of the conventional variable displacement swash plate type compressor, showing components related to coupling the lug plate 30 and the swash plate 40 of the compressor 10. The sidewalls 35 of the power transmission groove 31 of the lug plate 30 are formed at front and rear sides in a rotational direction of the drive shaft 20. The power transmission groove 31 is constituted by two slopes 34 and a rear groove 33 disposed between the slopes 34. The slide blocks 43 installed at both sides of the projection 41 disposed at a front center of the swash plate 40 are rolled on the slopes 34 to vary an inclination angle of the swash plate 40. In addition, the rear groove 33 prevents direct contact between the lug plate 30 and the swash plate 40 to minimize wearing of members during power transmission and slope movement guide. Meanwhile, side grooves 32 are formed in the both sidewalls of the power transmission groove 31 to prevent the swash plate 40 from coming off due to insertion of a pin 42 into the grooves 32, when the swash plate 40 moves along the slope.
FIG. 3 is a perspective view showing a rear surface of the lug plate 30 of the conventional variable displacement swash plate type compressor. In addition to the description of FIG. 2, a reinforcement rib 36 connecting a rear surface of the sidewall 35 of the lug plate 30 to a rear surface of the lug plate 30 is configured to prevent deformation of the lug plate 30 due to rotational movement thereof. Inner surfaces 37 of the sidewalls 35 of the lug plate 30 contacts with the slide blocks 43 to transmit rotational movement of the lug plate 30 to the swash plate 40 through the slide blocks 43.
FIG. 4 is a perspective view showing a front surface of the swash plate 40 of the conventional variable displacement swash plate type compressor. In addition to the description of FIG. 2, an insertion hole 44 is formed in the swash plate 40. A sleeve inserted into the drive shaft through the insertion hole 44 is coupled to the swash plate 40 to prevent the swash plate 40 from being separated from the center of the drive shaft.
According to the conventional art, the side surfaces of the slide blocks perform power transmission and the peripheral surfaces of the slide blocks perform slope movement guide to prevent direct contact between the lug plate and the swash plate, thereby minimizing wearing of the members and facilitating slope movement of the swash plate.